| Περίληψη: | The main idea of the present thesis is the examination of hydrogels for their use as drug carriers in drug delivery systems. Hydrogels are three-dimensional structures, composed of organic resources that have a very high swelling ability in aqueous solutions. Due to their special physical and chemical properties, such as flexibility, swell-ability, softness, and biocompatibility there is growing research interest in their synthesis, swelling and drug release mechanisms, all three of which are discussed in this thesis.
The synthesis of hydrogels involves physical, chemical and hybrid bonding and can be comprised of natural or synthetic polymers. Cross-linking agents are also used for a better stability and structure of the hydrogel network, while several mechanisms can be employed to enhance the gel’s properties and expand the variety of the drugs that can be possibly carried. In this work, salt carboxymethylcellu-lose (NaCMC) is chosen as the polymer for the hydrogel synthesis, citric acid is used as a cross-linking agent, while samples of unenhanced and enhanced hydrogels with β-cyclodextrin were prepared and contrasted.
The ability to display a measurable change in volume by swelling, in response to external stimuli is a fundamental property of hydrogels. Their swelling behavior may be described using many different models. Understanding these models, and the situations in which they may apply, is important with regard to the use of these materials. Most dynamic gel swelling models are based on Fick’s law of dif-fusion, while others exhibit non-Fickian behavior. The time-dependent concentration profile of the diffusing hydrogels was measured and modeled by comparing two different swelling kinetic equations: the Peppas equation and the second kinetic equation of diffusion.
Hydrogels can also be used in drug delivery. Hydrogel delivery systems can leverage therapeutically beneficial outcomes of drug delivery and have found clinical use. Hydrogels can provide spatial and temporal control over the release of various therapeutic agents, including small-molecule drugs, mac-romolecular drugs and cells. Their effectiveness may be extended via several mechanisms such as drug-hydrogel interactions and gel-network engineering, while remote or endogenous triggers can control the drug delivery and release. The drug release kinetics and mechanisms of samples with dif-ferent concentrations were studied and contrasted. The experiments were conducted using two dif-ferent bioactive compounds with different hydrophobicity: ketoconazole and fluconazole, obtaining different results depending on the hydrophobicity of each drug
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